The present invention relates to an improved fan exit guide vane installation system for use in gas turbines.
In a gas turbine engine used for propulsion, a fan case and a smaller diameter compressor case cooperate to radially bound an annular fan duct. Fan exit guide vanes span across the fan duct to de-swirl working medium fluid flowing therethrough. The outer and inner extremities of the vanes are connected to the fan and compressor cases respectively. Traditionally, the outer connection is effected by a pair of bolts. The inner connection, by contrast, includes numerous parts including spacers, nuts, bolts, and inserts.
This type of system presents problems from a replacement or maintenance standpoint. Occasionally, a vane will become damaged in use and need to be replaced. Using the connection system described above, replacement of a single damaged vane is difficult. In U.S. Pat. No. 5,690,469 to Deal et al., the issue of replacing a vane is addressed. In this patent, a repair kit for replacing an unserviceable vane assembly is described. The repair kit includes a serviceable vane subassembly having a serviceable airfoil with a base attached to the root end and an opposing base which is unattached to, but slidably engagable with the serviceable airfoil. The opposing base is slipped over the tip end of the airfoil and slid toward the base attached to the root end. The vane subassembly and opposing base are pivoted into position between inner and outer engine cases in place of an unserviceable vane assembly so that sockets in the attached base engage support pins extending from the inner case. An adhesive is applied to the tip end of the serviceable airfoil and the opposing base is translated into its installed position near the tip end of the serviceable airfoil. Upon curing of the adhesive, the opposing base becomes attached to the airfoil. The base is secured to the outer case by studs and nuts.
There is a need for a simpler system for installing fan exit guide vanes which reduces the quantity of parts, the cost of the parts, and the weight of the parts. There is also a need for a simpler system which facilities the repair of damaged vanes.